PythonOcc实战——step文件导入、零件识别、几何属性、爆炸图初步展示-程序员宅基地
技术标签： 3d python 可视化 cad PythonOcc
本系列文章主要是基于PythonOcc模块进行实例编程。本文主要想实现的功能是将step模型文件加载并封装到pyqt5自制的UI界面中，并初步实现零件识别、零件几何属性计算、产品爆炸图初步展示。
阅读并实现本系列文章需要一定的基础，请参考：
小新快跑
import sys
from PyQt5.QtWidgets import QMainWindow, QAction, qApp, QApplication
from OCC.Core.BRepPrimAPI import BRepPrimAPI_MakeBox#引入Occ模型绘制模块
from SelfMadeQTviewer3D import qtViewer3d#引入自己修改后的Occ3维模型展示模块，该模块并不通用，
#是由本人修改源代码之后才能使用的，源代码中不能直接import qtViewer3d
#该代码参考https://blog.csdn.net/weixin_42755384/article/details/87925748
class Example(QMainWindow):
def __init__(self):
super().__init__()
self.canva = qtViewer3d(self)
self.initUI()
def initUI(self):
exitAct = QAction('&Exit', self)
exitAct.setShortcut('Ctrl+Q')
exitAct.setStatusTip('Exit application')
exitAct.triggered.connect(qApp.quit)
self.statusBar()
menubar = self.menuBar()
fileMenu = menubar.addMenu('&File')
fileMenu.addAction(exitAct)
self.setGeometry(300, 100, 1600, 800)
self.setWindowTitle('PyOcc Packed In Pyqt5')
boxshp = BRepPrimAPI_MakeBox(50., 50., 50.).Shape()#绘制occ3维CAD模型
self.canva._display.DisplayShape(boxshp, update=True)[0]#在画布上展示occ3维CAD模型
self.setCentralWidget(self.canva)#在画布上展示occ3维CAD模型
self.show()
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
以上代码可以得到将occ封装入自定义pyqt5的UI界面，如下图所示，关键是：
from SelfMadeQTviewer3D import qtViewer3d。
接下来将进入实战。将STEP文件导入到PythonOcc中并实现零件识别、零件几何属性计算：
import sys
import time
from math import pi
import random
from OCC.Core.gp import gp_Ax1, gp_Pnt, gp_Dir, gp_Trsf # 引入Occ模型几何尺寸元素模块
from OCC.Core.TopLoc import TopLoc_Location # 引入Occ模型定位模块
from PyQt5.QtWidgets import QMainWindow, QAction, qApp, QApplication
from SelfMadeQTviewer3D import qtViewer3d # 引入自己修改后的Occ3维模型展示模块
from OCC.Extend.DataExchange import read_step_file#STEP文件导入模块
from OCC.Extend.TopologyUtils import TopologyExplorer#STEP文件导入模块后的拓扑几何分析模块
from OCC.Core.Quantity import Quantity_Color, Quantity_TOC_RGB
from OCC.Core.GProp import GProp_GProps#几何模型属性
from OCC.Core.BRepGProp import brepgprop_VolumeProperties#solid几何模型属性
class Example(QMainWindow):
def __init__(self):
super().__init__()
self.canva = qtViewer3d(self)
self.initUI()
def initUI(self):
exitAct = QAction('&Exit', self)
exitAct.setShortcut('Ctrl+Q')
exitAct.setStatusTip('Exit application')
exitAct.triggered.connect(qApp.quit)
self.statusBar()
menubar = self.menuBar()
fileMenu = menubar.addMenu('&File')
fileMenu.addAction(exitAct)
self.setGeometry(100, 50, 1200, 900)
self.setWindowTitle('PyOcc Packed In Pyqt5')
self.setCentralWidget(self.canva)
self.StepModelExplore()
self.show()
def STEP_shape(self):
stpshp = read_step_file('GateValveAssembly.STEP')# 读取step文件
return TopologyExplorer(stpshp)# step文件模型解析
def StepModelExplore(self):
self.canva._display.EraseAll()
self.STEPshp = self.STEP_shape()
i=0
for solid in self.STEPshp.solids():
i=i+1#用于统计零件数目
props = GProp_GProps()#获取几何属性查询函数
brepgprop_VolumeProperties(solid, props)#计算出当前solid的集合属性
#matrix_of_inertia = props.MatrixOfInertia()#当前solid的惯性矩
cog = props.CentreOfMass()#当前solid的形心
cog_x, cog_y, cog_z = cog.Coord()
print("This Solid mass = %s" % props.Mass())#当前solid的体积
print("Center of Solid: x = %f;y = %f;z = %f;" % (cog_x, cog_y, cog_z))
color = Quantity_Color(random.random(), random.random(),random.random(),Quantity_TOC_RGB)
self.canva._display.DisplayColoredShape(solid, color)
print("零件数目为：%d" % (i))
self.canva._display.FitAll()
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
2
Number of shapes: 2
This Solid mass = 1671588.029631332
Center of Solid: x = 0.000025;y = 21.327333;z = -90.000000;
This Solid mass = 20416.786227435936
Center of Solid: x = -0.000001;y = 0.723585;z = -67.780266;
This Solid mass = 20416.786227435958
Center of Solid: x = -0.000000;y = 0.723584;z = -112.219734;
This Solid mass = 539264.8949639023
Center of Solid: x = -0.053763;y = 166.657923;z = -90.042440;
This Solid mass = 54103.19372018658
Center of Solid: x = -0.000000;y = 311.553234;z = -90.000000;
This Solid mass = 18954.852646672913
Center of Solid: x = -0.000000;y = 305.792553;z = -90.000000;
This Solid mass = 338469.4612692211
Center of Solid: x = 0.000015;y = 337.857166;z = -90.000001;
This Solid mass = 5220.770297180713
Center of Solid: x = 0.000000;y = 344.000954;z = -90.000000;
This Solid mass = 49449.28479252284
Center of Solid: x = -0.000000;y = 114.460108;z = -90.000000;
This Solid mass = 39139.64044792523
Center of Solid: x = -0.199089;y = 283.199322;z = -90.325002;
This Solid mass = 106966.64358232789
Center of Solid: x = -0.000000;y = 11.964572;z = -90.000007;
This Solid mass = 4781.860167653959
Center of Solid: x = -2.724443;y = 192.999999;z = -42.000000;
This Solid mass = 1309.926227762865
Center of Solid: x = 20.706363;y = 193.000002;z = -42.000000;
This Solid mass = 12662.473567635041
Center of Solid: x = 0.000000;y = 214.240225;z = -42.000000;
This Solid mass = 4781.860167653957
Center of Solid: x = -2.724443;y = 192.999999;z = -138.000000;
This Solid mass = 1309.9262277628643
Center of Solid: x = 20.693637;y = 193.000002;z = -138.000000;
This Solid mass = 12662.473567635043
Center of Solid: x = 0.000000;y = 214.240225;z = -138.000000;
This Solid mass = 36769.10249043011
Center of Solid: x = 0.000000;y = 232.763354;z = -89.999999;
This Solid mass = 10777.165686221655
Center of Solid: x = -0.000000;y = 214.799317;z = -90.000000;
This Solid mass = 1998.9380995506442
Center of Solid: x = -0.000003;y = 244.471533;z = -42.000001;
This Solid mass = 1998.9380995506447
Center of Solid: x = 0.000002;y = 244.471533;z = -137.999998;
This Solid mass = 4.188790204786394
Center of Solid: x = -0.000000;y = 290.500000;z = -47.000000;
This Solid mass = 951.8048002047907
Center of Solid: x = -0.000000;y = 290.500000;z = -56.794693;
This Solid mass = 9196.595426332882
Center of Solid: x = 35.652961;y = 189.204163;z = -62.957503;
This Solid mass = 14.137166941154069
Center of Solid: x = 47.994656;y = 189.204163;z = -52.963397;
This Solid mass = 3131.1503837897526
Center of Solid: x = 0.000000;y = 106.500000;z = -90.000000;
This Solid mass = 12743.227021776174
Center of Solid: x = -0.000000;y = 139.414294;z = -90.000000;
This Solid mass = 5046.897424302504
Center of Solid: x = -0.000004;y = 178.999999;z = -89.999996;
This Solid mass = 2377.662039991875
Center of Solid: x = -0.000000;y = 166.750000;z = -90.000000;
This Solid mass = 2377.662039991875
Center of Solid: x = 0.000000;y = 158.250000;z = -90.000000;
This Solid mass = 2377.6620399918756
Center of Solid: x = -0.000000;y = 191.250000;z = -90.000000;
This Solid mass = 2377.662039991875
Center of Solid: x = -0.000000;y = 199.750000;z = -90.000000;
This Solid mass = 4813.889207068303
Center of Solid: x = 48.000000;y = 131.400017;z = -37.999999;
This Solid mass = 4813.889207068301
Center of Solid: x = -48.000000;y = 131.400017;z = -38.000001;
This Solid mass = 4813.889207068301
Center of Solid: x = 48.000000;y = 131.400017;z = -142.000001;
This Solid mass = 4813.889207068301
Center of Solid: x = -48.000000;y = 131.400017;z = -142.000001;
This Solid mass = 4813.889207068302
Center of Solid: x = 48.000000;y = 78.599983;z = -141.999999;
This Solid mass = 4813.889207068303
Center of Solid: x = 48.000000;y = 78.599983;z = -37.999999;
This Solid mass = 4813.889207068305
Center of Solid: x = -48.000000;y = 78.599983;z = -141.999999;
This Solid mass = 4813.889207068301
Center of Solid: x = -48.000001;y = 78.599983;z = -37.999999;
This Solid mass = 16082.638427578428
Center of Solid: x = 48.000000;y = 105.372204;z = -38.000000;
This Solid mass = 16082.638427578428
Center of Solid: x = -48.000000;y = 105.372204;z = -38.000000;
This Solid mass = 16082.638427578428
Center of Solid: x = 48.000000;y = 105.372204;z = -142.000000;
This Solid mass = 16082.638427578413
Center of Solid: x = -48.000000;y = 105.372204;z = -142.000000;
零件数目为：44
该零件数目统计结果与用solidworks等商业软件导入文件时的结果一致。
下面要做爆炸图展示，想法是根据各个零件形心所在位置按照不同方向比例做平移。
import sys
import time
from math import pi
import random
from OCC.Core.gp import gp_Ax1, gp_Pnt, gp_Dir, gp_Trsf ,gp_Vec # 引入Occ模型几何尺寸元素模块，零件移动关键模块
from OCC.Core.TopLoc import TopLoc_Location # 引入Occ模型定位模块
from PyQt5.QtWidgets import QMainWindow, QAction, qApp, QApplication
from SelfMadeQTviewer3D import qtViewer3d # 引入自己修改后的Occ3维模型展示模块
from OCC.Extend.DataExchange import read_step_file#STEP文件导入模块
from OCC.Extend.TopologyUtils import TopologyExplorer#STEP文件导入模块后的拓扑几何分析模块
from OCC.Core.Quantity import Quantity_Color, Quantity_TOC_RGB
from OCC.Core.GProp import GProp_GProps#几何模型属性
from OCC.Core.BRepGProp import brepgprop_VolumeProperties#solid几何模型属性
class Example(QMainWindow):
def __init__(self):
super().__init__()
self.canva = qtViewer3d(self)
self.initUI()
def initUI(self):
exitAct = QAction('&Exit', self)
exitAct.setShortcut('Ctrl+Q')
exitAct.setStatusTip('Exit application')
exitAct.triggered.connect(qApp.quit)
self.statusBar()
menubar = self.menuBar()
fileMenu = menubar.addMenu('&File')
fileMenu.addAction(exitAct)
self.setGeometry(100, 50, 1200, 900)
self.setWindowTitle('PyOcc Packed In Pyqt5')
self.setCentralWidget(self.canva)
self.StepModelExplore()
self.show()
def STEP_shape(self):
stpshp = read_step_file('GateValveAssembly.STEP')# 读取step文件
return TopologyExplorer(stpshp)# step文件模型解析
def StepModelExplore(self):
self.canva._display.EraseAll()
self.STEPshp = self.STEP_shape()
i=0
for solid in self.STEPshp.solids():
i=i+1#用于统计零件数目
props = GProp_GProps()#获取几何属性查询函数
brepgprop_VolumeProperties(solid, props)#计算出当前solid的集合属性
#matrix_of_inertia = props.MatrixOfInertia()#当前solid的惯性矩
cog = props.CentreOfMass()#当前solid的形心
cog_x, cog_y, cog_z = cog.Coord()
print("This Solid mass = %s" % props.Mass())#当前solid的体积
# print("Center of Solid: x = %f;y = %f;z = %f;" % (cog_x, cog_y, cog_z))
# ----------爆炸图展示载入的3维模型----------------------
T=gp_Trsf()#定义一个变换函数
T.SetTranslation(gp_Vec(5*cog_x,5*cog_y,10*cog_z))#将变换函数设置为沿着指定向量平移
loc=TopLoc_Location(T)#将变换函数重新定位到几何拓扑上
solid.Location(loc)#将该几何拓扑solid定位
# ----------爆炸图展示载入的3维模型----------------------
color = Quantity_Color(random.random(), random.random(),random.random(),Quantity_TOC_RGB)
self.canva._display.DisplayColoredShape(solid, color)
print("零件数目为：%d" % (i))
self.canva._display.FitAll()
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
2
Number of shapes: 2
This Solid mass = 1671588.029631332
This Solid mass = 20416.786227435936
This Solid mass = 20416.786227435958
This Solid mass = 539264.8949639023
This Solid mass = 54103.19372018658
This Solid mass = 18954.852646672913
This Solid mass = 338469.4612692211
This Solid mass = 5220.770297180713
This Solid mass = 49449.28479252284
This Solid mass = 39139.64044792523
This Solid mass = 106966.64358232789
This Solid mass = 4781.860167653959
This Solid mass = 1309.926227762865
This Solid mass = 12662.473567635041
This Solid mass = 4781.860167653957
This Solid mass = 1309.9262277628643
This Solid mass = 12662.473567635043
This Solid mass = 36769.10249043011
This Solid mass = 10777.165686221655
This Solid mass = 1998.9380995506442
This Solid mass = 1998.9380995506447
This Solid mass = 4.188790204786394
This Solid mass = 951.8048002047907
This Solid mass = 9196.595426332882
This Solid mass = 14.137166941154069
This Solid mass = 3131.1503837897526
This Solid mass = 12743.227021776174
This Solid mass = 5046.897424302504
This Solid mass = 2377.662039991875
This Solid mass = 2377.662039991875
This Solid mass = 2377.6620399918756
This Solid mass = 2377.662039991875
This Solid mass = 4813.889207068303
This Solid mass = 4813.889207068301
This Solid mass = 4813.889207068301
This Solid mass = 4813.889207068301
This Solid mass = 4813.889207068302
This Solid mass = 4813.889207068303
This Solid mass = 4813.889207068305
This Solid mass = 4813.889207068301
This Solid mass = 16082.638427578428
This Solid mass = 16082.638427578428
This Solid mass = 16082.638427578428
This Solid mass = 16082.638427578413
零件数目为：44
最终爆炸图结果如下所示：
实际上，经过深入理解step文件内容，可以实现每一个零件的特征认定（比如step文件中颜色、材料、体积等），并实现对任意零件的操作（平移、旋转、删除）
SelfMadeQTviewer3D.py文件内容如下：
import ctypes
import logging
import os
import sys
from OCC.Display import OCCViewer
from PyQt5 import QtCore, QtGui, QtOpenGL, QtWidgets
# check if signal available, not available
# on PySide
HAVE_PYQT_SIGNAL = hasattr(QtCore, 'pyqtSignal')
logging.basicConfig(stream=sys.stdout, level=logging.DEBUG)
log = logging.getLogger(__name__)
class qtBaseViewer(QtOpenGL.QGLWidget):
''' The base Qt Widget for an OCC viewer
'''
def __init__(self, parent=None):
super(qtBaseViewer, self).__init__(parent)
self._display = OCCViewer.Viewer3d()
self._inited = False
# enable Mouse Tracking
self.setMouseTracking(True)
# Strong focus
self.setFocusPolicy(QtCore.Qt.WheelFocus)
self.setAttribute(QtCore.Qt.WA_NativeWindow)
self.setAttribute(QtCore.Qt.WA_PaintOnScreen)
self.setAttribute(QtCore.Qt.WA_NoSystemBackground)
self.setAutoFillBackground(False)
def GetHandle(self):
''' returns an the identifier of the GUI widget.
It must be an integer
'''
win_id = self.winId() # this returns either an int or voitptr
if "%s" % type(win_id) == "<type 'PyCObject'>": # PySide
### with PySide, self.winId() does not return an integer
if sys.platform == "win32":
## Be careful, this hack is py27 specific
## does not work with python31 or higher
## since the PyCObject api was changed
ctypes.pythonapi.PyCObject_AsVoidPtr.restype = ctypes.c_void_p
ctypes.pythonapi.PyCObject_AsVoidPtr.argtypes = [ctypes.py_object]
win_id = ctypes.pythonapi.PyCObject_AsVoidPtr(win_id)
elif not isinstance(win_id, int): # PyQt4 or 5
## below integer cast may be required because self.winId() can
## returns a sip.voitptr according to the PyQt version used
## as well as the python version
win_id = int(win_id)
return win_id
def resizeEvent(self, event):
super(qtBaseViewer, self).resizeEvent(event)
self._display.View.MustBeResized()
def paintEngine(self):
return None
class qtViewer3d(qtBaseViewer):
# emit signal when selection is changed
# is a list of TopoDS_*
if HAVE_PYQT_SIGNAL:
sig_topods_selected = QtCore.pyqtSignal(list)
def __init__(self, *kargs):
qtBaseViewer.__init__(self, *kargs)
self.setObjectName("qt_viewer_3d")
self._drawbox = False
self._zoom_area = False
self._select_area = False
self._inited = False
self._leftisdown = False
self._middleisdown = False
self._rightisdown = False
self._selection = None
self._drawtext = True
self._qApp = QtWidgets.QApplication.instance()
self._key_map = {
}
self._current_cursor = "arrow"
self._available_cursors = {
}
@property
def qApp(self):
# reference to QApplication instance
return self._qApp
@qApp.setter
def qApp(self, value):
self._qApp = value
def InitDriver(self):
self._display.Create(window_handle=self.GetHandle(), parent=self)
# background gradient
self._display.SetModeShaded()
self._inited = True
# dict mapping keys to functions
self._key_map = {
ord('W'): self._display.SetModeWireFrame,
ord('S'): self._display.SetModeShaded,
ord('A'): self._display.EnableAntiAliasing,
ord('B'): self._display.DisableAntiAliasing,
ord('H'): self._display.SetModeHLR,
ord('F'): self._display.FitAll,
ord('G'): self._display.SetSelectionMode}
self.createCursors()
def createCursors(self):
module_pth = os.path.abspath(os.path.dirname(__file__))
icon_pth = os.path.join(module_pth, "icons")
_CURSOR_PIX_ROT = QtGui.QPixmap(os.path.join(icon_pth, "cursor-rotate.png"))
_CURSOR_PIX_PAN = QtGui.QPixmap(os.path.join(icon_pth, "cursor-pan.png"))
_CURSOR_PIX_ZOOM = QtGui.QPixmap(os.path.join(icon_pth, "cursor-magnify.png"))
_CURSOR_PIX_ZOOM_AREA = QtGui.QPixmap(os.path.join(icon_pth, "cursor-magnify-area.png"))
self._available_cursors = {
"arrow": QtGui.QCursor(QtCore.Qt.ArrowCursor), # default
"pan": QtGui.QCursor(_CURSOR_PIX_PAN),
"rotate": QtGui.QCursor(_CURSOR_PIX_ROT),
"zoom": QtGui.QCursor(_CURSOR_PIX_ZOOM),
"zoom-area": QtGui.QCursor(_CURSOR_PIX_ZOOM_AREA),
}
self._current_cursor = "arrow"
def keyPressEvent(self, event):
code = event.key()
if code in self._key_map:
self._key_map[code]()
elif code in range(256):
log.info('key: "%s"(code %i) not mapped to any function' % (chr(code), code))
else:
log.info('key: code %i not mapped to any function' % code)
def focusInEvent(self, event):
if self._inited:
self._display.Repaint()
def focusOutEvent(self, event):
if self._inited:
self._display.Repaint()
def paintEvent(self, event):
if not self._inited:
self.InitDriver()
self._display.Context.UpdateCurrentViewer()
if self._drawbox:
painter = QtGui.QPainter(self)
painter.setPen(QtGui.QPen(QtGui.QColor(0, 0, 0), 2))
rect = QtCore.QRect(*self._drawbox)
painter.drawRect(rect)
def wheelEvent(self, event):
try: # PyQt4/PySide
delta = event.delta()
except: # PyQt5
delta = event.angleDelta().y()
if delta > 0:
zoom_factor = 2.
else:
zoom_factor = 0.5
self._display.ZoomFactor(zoom_factor)
@property
def cursor(self):
return self._current_cursor
@cursor.setter
def cursor(self, value):
if not self._current_cursor == value:
self._current_cursor = value
cursor = self._available_cursors.get(value)
if cursor:
self.qApp.setOverrideCursor(cursor)
else:
self.qApp.restoreOverrideCursor()
def mousePressEvent(self, event):
self.setFocus()
ev = event.pos()
self.dragStartPosX = ev.x()
self.dragStartPosY = ev.y()
self._display.StartRotation(self.dragStartPosX, self.dragStartPosY)
def mouseReleaseEvent(self, event):
pt = event.pos()
modifiers = event.modifiers()
if event.button() == QtCore.Qt.LeftButton:
if self._select_area:
[Xmin, Ymin, dx, dy] = self._drawbox
self._display.SelectArea(Xmin, Ymin, Xmin + dx, Ymin + dy)
self._select_area = False
else:
# multiple select if shift is pressed
if modifiers == QtCore.Qt.ShiftModifier:
self._display.ShiftSelect(pt.x(), pt.y())
else:
# single select otherwise
self._display.Select(pt.x(), pt.y())
if (self._display.selected_shapes is not None) and HAVE_PYQT_SIGNAL:
self.sig_topods_selected.emit(self._display.selected_shapes)
elif event.button() == QtCore.Qt.RightButton:
if self._zoom_area:
[Xmin, Ymin, dx, dy] = self._drawbox
self._display.ZoomArea(Xmin, Ymin, Xmin + dx, Ymin + dy)
self._zoom_area = False
self.cursor = "arrow"
def DrawBox(self, event):
tolerance = 2
pt = event.pos()
dx = pt.x() - self.dragStartPosX
dy = pt.y() - self.dragStartPosY
if abs(dx) <= tolerance and abs(dy) <= tolerance:
return
self._drawbox = [self.dragStartPosX, self.dragStartPosY, dx, dy]
def mouseMoveEvent(self, evt):
pt = evt.pos()
buttons = int(evt.buttons())
modifiers = evt.modifiers()
# ROTATE
if (buttons == QtCore.Qt.LeftButton and
not modifiers == QtCore.Qt.ShiftModifier):
self.cursor = "rotate"
self._display.Rotation(pt.x(), pt.y())
self._drawbox = False
# DYNAMIC ZOOM
elif (buttons == QtCore.Qt.RightButton and
not modifiers == QtCore.Qt.ShiftModifier):
self.cursor = "zoom"
self._display.Repaint()
self._display.DynamicZoom(abs(self.dragStartPosX),
abs(self.dragStartPosY), abs(pt.x()),
abs(pt.y()))
self.dragStartPosX = pt.x()
self.dragStartPosY = pt.y()
self._drawbox = False
# PAN
elif buttons == QtCore.Qt.MidButton:
dx = pt.x() - self.dragStartPosX
dy = pt.y() - self.dragStartPosY
self.dragStartPosX = pt.x()
self.dragStartPosY = pt.y()
self.cursor = "pan"
self._display.Pan(dx, -dy)
self._drawbox = False
# DRAW BOX
# ZOOM WINDOW
elif (buttons == QtCore.Qt.RightButton and
modifiers == QtCore.Qt.ShiftModifier):
self._zoom_area = True
self.cursor = "zoom-area"
self.DrawBox(evt)
self.update()
# SELECT AREA
elif (buttons == QtCore.Qt.LeftButton and
modifiers == QtCore.Qt.ShiftModifier):
self._select_area = True
self.DrawBox(evt)
self.update()
else:
self._drawbox = False
self._display.MoveTo(pt.x(), pt.y())
self.cursor = "arrow"
版权声明：本文为博主原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。
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